3x^2-18x-87=0

Solution for 3x^2-18x-87=0 equation:

3x^2-18x-87=0

a = 3; b = -18; c = -87;
Δ = b2-4ac
Δ = -182-4·3·(-87)
Δ = 1368
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1368}=\sqrt{36*38}=\sqrt{36}*\sqrt{38}=6\sqrt{38}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-6\sqrt{38}}{2*3}=\frac{18-6\sqrt{38}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+6\sqrt{38}}{2*3}=\frac{18+6\sqrt{38}}{6}
$